Rocky Mountain (56th Annual) and Cordilleran (100th Annual) Joint Meeting (May 3–5, 2004)

Paper No. 16
Presentation Time: 8:00 AM-5:00 PM


SCHAEF, H. Todd, REIDEL, S.R. and MCGRAIL, B. Peter, Environmental Technology Directorate, Pacific Northwest National Lab, PO Box 999, Richland, WA 99352,

Flood basalt volcanism occurred in the Pacific Northwest between 17.5 and 6 Ma when over 300 basaltic lavas of the Columbia River Basalt Group were erupted from fissures in eastern Washington, eastern Oregon, and western Idaho. These flood-basalts cover over 200,000 km2 and have an estimated volume of more than 234,000 km3. Many of the lavas were of extraordinary size with some exceeding 10,000 km3 and traveling many hundreds of kilometers westward from vent systems. The presence of naturally occurring siderite and calcite indicate that the basalt flows have reacted with CO2 in the past. In order to understand these conditions and the potential for basalt to sequester greenhouse gases, we have under taken dissolution experiments. Steady-state dissolution rates of two samples of the Sentinel Bluffs Member, Grande Ronde Basalt were measured in a well-mixed batch reactor over a range of pH values (3.0 to 7.0) and temperatures (22º, 40º, 70º, and 90ºC). Results show that as the pH increases from 3 to 7, the dissolution rate decreases. When normalized by initial geometric surface area, the basalt samples have similar dissolution rates found in the literature for olivine, augite, anorthite, and basaltic glasses. These results show the potential basalt formations have to convert injected CO2 into solid carbonate minerals.